Surface Acoustic Wave (SAW) torque sensing is an emerging technology for automotive, transportation, rail and other similar segments for use, for example, in power train and chassis applications. Significant research and development efforts have resulted in the implementation of mass-produced SAW torque sensors at a cost-effective price. Engine transmission, driveline and chassis designers are now employing SAW torque sensors that provide a competitive edge with improved vehicle safety, performance and economy.
In general, a SAW sensor is a type of device composed of resonators whose resonant frequency changes when they are strained. Working at radio frequencies, such devices can be wirelessly excited with an interrogation pulse and a resonant frequency response measured allowing strain to be calculated. Torque can then be sensed by utilizing appropriate packaging and algorithms to deduce the value of sensed properties from a returned signal.
Conventional torque sensor designs employ SAW sensing elements arranged in a configuration that includes a two-piece metal enclosure that must be welded together and then welded to the shaft. Current designs additionally include wirebond posts oriented parallel to the shaft and the plane of the sensing element thereby creating difficulty in wire-bonding and antenna attachment.
Based on the foregoing, it is believed that a key to overcoming the aforementioned drawbacks of conventional torque sensing systems and devices involves the re-orienting of the posts and a reduction of the number of welding steps required to configure a torque sensor. The methods and systems disclosed herein provide a unique solution to the aforementioned drawbacks.